The invention relates to an array substrate and in particular to an array substrate for a wide-viewing angle liquid crystal display (LCD).
LCDs employ applied voltage to change the alignment of liquid crystal molecules, and resulting optical characteristics, such as double refraction, optical rotation, and dichromatism cause display variations. Due to thin profile, light weight, low power consumption, and low operating voltage, LCDs are widely employed in electronic products, such as portable personal computers, digital cameras, projectors, and the like.
Currently, LCD development is directed towards increased brightness, contrast, viewing angle, and large display area with full color display. To improve the viewing angle, a multi-domain vertical alignment liquid crystal display (MVALCD) has been developed, in which the display area of the LCD is divided into multiple domains, such that liquid crystal molecules incline at different angles to increase the viewing angle. In such an LCD, a pre-tilt angle controls the alignment of the liquid crystal, providing precise control of the inclination of the liquid crystal molecules. Commonly, slits and protrusions are employed to provide the pre-tilt angle.
FIG. 6 illustrates an array substrate 100 of a conventional MVALCD. The array substrate 100 comprises a glass substrate 101, a storage capacitor 102, an insulating layer 104, and a pixel electrode 106. The storage capacitor 102, the insulating layer 104, and the pixel electrode 106 are successively disposed on the glass substrate 100. The storage capacitor 102 includes a bottom electrode 102a, a capacitor dielectric layer 102b, and an upper electrode 102c, in which the upper electrode 102c is electrically connected to an overlying pixel electrode 106 through a contact hole 104a. The pixel electrode 106 has a slit 106a across the storage capacitor 102, to provide a pre-tilt angle.
The upper electrode 102c and the pixel electrode 106, however, have the same potential when voltage is applied to the pixel electrode 106 due to electrical connection, such that the slit 106a over the storage capacitor 102 (overlap region between the slit 106a and the storage capacitor 102) cannot provide a pre-tilt angle. Thus, disclination lines may be generated on the liquid crystal layer (not shown) near the slit 106a over the storage capacitor 102. The generated disclination lines can reduce the brightness and increase the response time of the LCD. In particular, color washout may become more serious due to the disclination lines, reducing image quality.